I. Pérez-Munuera

Microstructure Changes During the Xixona Turrón Manufacture Analyzed by Light Microscopy

Xixona turrón [Xixona nougat] is a typical Spanish confectionery product made still according to the traditional craft method. This work analyzed the microstructural changes during Xixona turrón manufacture by light microscopy. Different sample preparation methods provided useful complementary information for the understanding of the Xixona turrón structure. A progressively closer contact between a ‘‘sugar phase’’ and a ‘‘fat phase’’ is observed during processing. Inside these phases were immersed many protein bodies and a lot of cellular debris from almond tissue. At the initial stages of mixing the toasted almond paste with the sugar and honey mass, the lipid and sugar phases were relatively discrete. However, as the process developed, the relatively large aerated sugar particles, and to some extent the almond cell debris and protein bodies, were trapped within the lipid phase. In the step when the paste is heated at 65°C, gently stirred, the sugar and plant cell wall material tended to become more finely dispersed. The finished product seemed to consist of twin continuous phases in which the sugar, plant cell wall and protein bodies have formed a ‘‘sugar phase’’ that is infiltrated by the lipid fraction or ‘‘fat phase’’. This structure could contribute to the relatively ‘‘crispy’’ texture of Xixona turrón although the ‘‘oily’’ feel of the product clearly stated that the lipid phase was not extensively encapsulated in the product.

Manzana fresca cortada tratada con aditivos naturales: calidad y aspectos estructurales Fresh-cut apple treated with natural additives: quality and structural aspects

The effect of different natural additives on some quality parameters of fresh-cut Fuji apple is studied during 4 weeks of storage at 4°C. The results show that the calcium lactate maintains the texture and improves the structure of the fresh-cut apple during the storage. It strengthens the cell walls due to the formation of calcium pectates. The combination of cysteine and glutathione is effective at inhibiting the browning of the fruit as it maintains the colour during the storage. Furthermore, these antibrowning compounds do not interfere with the calcium when it is used as firming agent. Finally, although benzaldehyde and malic acid show better results than the synthetic antimicrobials usually used, malic acid shows lower microbial counts and it is easier to apply. So, the combined treatment using natural additives, which includes calcium lactate, cysteine, glutathione and malic acid, is appropriate to maintain the quality of the fresh-cut Fuji apple. Este trabajo estudia el efecto de distintos tratamientos con aditivos naturales sobre algunas características de calidad de manzana Fuji fresca cortada, durante cuatro semanas de almacenamiento a 4°C. Los resultados muestran que el lactato cálcico mantiene la textura y mejora la estructura de la manzana fresca cortada, ya que refuerza las paredes celulares mediante la formación de pectatos cálcicos. La combinación de cisteína/glutatión, usada como antioxidante, es eficaz manteniendo el color a lo largo del almacenamiento y no interfiere en la acción del calcio como reafirmante de la estructura. Por último, aunque tanto el benzaldehído como el ácido málico presentan mejores resultados como antimicrobianos que los sintéticos utilizados habitualmente, el ácido málico muestra recuentos microbianos inferiores y una mayor facilidad de aplicación. Por tanto, el tratamiento de origen natural compuesto por lactato cálcico, cisteína, glutatión y ácido málico es adecuado para mantener la calidad de la manzana Fuji fresca cortada.

Microstructural changes in dough treated by Glucose oxidase (GOX) and Transglutaminase (TG), studied by Scanning Electron Microscopy (SEM)

The improvement of dough functionality through different enzymes is a new strategy used in the last years for the bakery industry. Some enzymes as glucose oxidase (GOX, EC 1.1.3.4) and transglutaminase (TG, EC 2.3.2.13) modify the protein fraction, mainly the gluten proteins, but is not well-known the influence of these enzymes on the structure of the dough components [1, 2].

Microstructure of model systems for sauces based in polysacharides observed by Cryo-SEM

The demand for foodstuffs which are easily and fast prepared has increased considerably in recent years. Sauces are often used in this kind of products and their formulation usually includes polysaccharides (starch and/or gums) as thickening agents [1]. Sauce microstructure gives information about the components arrangement and how it affects physical and chemical properties such as viscosity. The aim of this work is to study the effect of different thickeners and salt concentrations on the microstructure of model systems.

Microstructural changes produced by Pulsed Electric Fields in liquid whole egg studied by Transmission Electron Microscopy (TEM)

The application of new technologies for food processing and preservation aims to meet to the increasing number of catering companies due to the growing demand for fresh foods, high quality and ready-to-eat meals. Among the non-thermal technologies for food preservation, the application of Pulsed Electric Fields (PEF) is receiving big attention over the past few years, as it reduces the detrimental changes on physical and sensorial properties of foods and offers fresh fluid foods of high quality, taste, nutritional value and improved shelf-life [1, 2].

Studies on the microstructure of fresh-cut melon

Fresh-cut fruit is a segment of food industry that is developing fast due to the fact that it is a convenient food and has a fresh-like quality. However, fresh-cut fruits are still under research because of the problems involved in preserving their quality during prolonged periods. In order to improve their texture, postharvest calcium solution application has been used [1]. Calcium maintains the cell wall structure in fruits by interacting with pectic acid in the cell wall to form calcium pectate which firms molecular bonding between constituents of cell wall [2]. The aim of this work is to study the effect of calcium lactate on the microstructure of fresh-cut Piel de Sapo melon during three weeks of storage at 4°C.